811 “Call before you Dig”
There is no standard answer as to the proper location for real estate signs, as underground utilities can vary from location to location. The best and safest way to determine where a sign, mailbox, bush, tree, etc., may be located is to call 811 or visit www.usanorth811.org for a utility locate prior to installing. This is a nationwide service which allows the public to make a single call which is then transmitted to the relevant utility operators for your location . . . it’s simple & it’s free!
For Northern/Central California and all of Nevada, calling 811 or visiting www.usanorth811.org will connect you to USA North, and they recommend making contact “2 working days to 14 calendar days before you dig in California.” This does not necessarily mean that it will take 14 days for the specific utilities to respond, but rather do not call more than 14 days in advance so your markings will not have disappeared by the time you dig. In other words, call two working days in advance, excluding weekends and holidays, of your dig.
The following links provide guidelines and/or other useful information as to when to call for a utility locate: